Some conveyor systems are provided to handle overlapping substantially flat items to be carried along a transport path. Examples of such items include packages provided in the form of folded boxes coming out of a folding and gluing machine. Some of these packages have a non-uniform thickness and a non-symmetrical shape when folded. Handling these items using conveyors can be challenging in some cases, particularly when high volumes and high speeds are involved. For instance, such items are often prone to slippage with reference to one another, especially when the conveyor system accelerates and decelerates. This slippage can cause local shifts in the relative position of items, thereby creating local variations in thickness. These variations in thickness of the shingled stream along its length generally complicate the handling of the items.
Items handled in conveyor systems have a certain degree of flexibility, which depends on various factors such as the material used, the orientation of the material, etc. However, when a maximum bending angle of an item is exceeded somewhere along a transport path, a plastic deformation will occur and this can often leave a visible trace somewhere on the items, usually in the form of a transversal crease on at least one of its major sides. This somewhat alters the aesthetic aspect of the items and is thus generally undesirable.
Conveyor systems may sometimes include a mechanism for selectively directing some successive items in one direction and other successive items in at least one other direction. U.S. Pat. No. 7,360,636 (Theriault) issued 22 Apr. 2008, the contents of which is hereby incorporated by reference, discloses an example of an apparatus including a conveyor system for handling a shingle of items. This apparatus can automatically alternate the orientation of the items so as to optimize the storage space when they are stacked, for instance inside a shipping box. The apparatus includes a diverter in the form of a flap whose position directs the items in one among two possible transport paths.
One of the main advantages of using a flap is that it is simple. However, the items are unsupported when passing around the flap and this may create some difficulties if the items are relatively short in length, especially if their length is less than the distance between the incoming conveyor and the corresponding outgoing conveyor. Reducing the distance between the two conveyors can solve this problem. However, decreasing the distance will increase the bending angle to which the items are subjected when passing through one or more of the possible transport paths, thereby increasing the risks of exceeding the maximum bending angle somewhere within the conveyor system.
Another possible approach for selectively directing a shingled stream of items through two or more possible transport paths is to provide an actuated arrangement at the downstream end portion of the incoming conveyor that can be selectively repositioned to be in registry with the selected outgoing conveyor. Such arrangement is called hereafter a “diverter”. In practice, the space available for the diverter can often be very limited and providing such diverter can be challenging. Even when the available space is not an issue, minimizing the length of the diverter is still generally desirable, for instance to reduce manufacturing costs, weight and complexity. An excessively long diverter would require more powerful actuators and will take a longer time to be repositioned compared to a shorter one.
Accordingly, there is still room for improvements in this area of technology.